1. Field
One or more embodiments of the present invention relate to a method of manufacturing a flexible display device, and more particularly, to a method of manufacturing a flexible display device, whereby a display unit including a thin film transistor (TFT) is easily cut.
2. Description of the Related Technology
The market for liquid crystal display (LCD) devices including a thin film transistor (TFT), and for organic light emitting display devices has expanded toward displays for mobile devices including digital cameras, video cameras, Portable Digital Assistants (PDAs), and the like.
It is desirable for such displays to be thin, lightweight, and durable against breakage. In order to manufacture thin and lightweight displays, a thin glass substrate is typically used. A method has been introduced whereby a substrate is manufactured by using an existing glass substrate, and then the glass substrate is mechanically or chemically thinned. However, this method may present some problems, such as complicated procedures, and easy breakage of the glass substrate making it difficult to use.
It is also desirable for the mobile devices to be flexible to accommodate a curved surface, so as to become display devices having various shapes. However, it is generally difficult to implement flexibility when using an existing glass substrate.
In order to address some of these problems, there has been an attempt to form a low temperature polycrystalline silicon TFT on a plastic substrate. Plastic is not easily broken even when the plastic has a thickness of only about 0.2 mm, and weight of plastic is typically less than glass, so that weight of a plastic substrate may be equal to or less than a fifth of the weight of an existing glass substrate, making it possible to implement a curved surface by using the plastic substrate.
However, if the plastic substrate is made thin, when a TFT and a display device are sequentially formed on the plastic substrate, the plastic substrate may not be able to hold a load due to the plastic substrate's flexible characteristic, and thus it may be difficult to handle the plastic substrate.
In order to address this problem, research is being conducted to form a thin plastic substrate on a glass substrate, to form a display unit including a TFT and a display device on the thin plastic substrate, and then to separate the glass substrate from the plastic substrate. Generally, a plurality of the display units are formed on a substrate having a large area, and the plurality of the display units are then cut into units of panels. This necessitates cutting two substrates, the glass substrate and the plastic substrate, and such a substrate-cutting process is not generally easy.